This invention relates to a rapping mechanism for rapping a row of electrodes in an electrostatic precipitator. Such electrodes consist of vertical strip plates suspended from their upper ends, and the rapping mechanism comprises a horizontal rapping bar connecting with the lower end of each electrode in the row and a hammer for striking the bar in its axial direction.
A rapping mechanism of the above kind is known from US-A-3844742. The mechanism is utilised for shaking or vibration of the collecting electrodes in an electrostatic precipitator at regular intervals in order to remove dust deposited on the electrodes and resulting from flue gases passed through the electrostatic precipitator which is used for removal of dust particles. Such a mechanism will hereinafter be referred to as "of the above kind".
As illustrated in the accompanying FIGS. 1, 2 and 3, the connection between the lower ends of the electrodes and the rapping mechanism can, in known manner, be such that the rapping bar is fastened to the electrodes with bolts, that the rapping bar acts upon the electrodes through tongues welded to the lower end of the electrodes, or that the rapping bar acts directly on an edge of the electrodes.
However, in the first two examples mentioned above the effect of the peak force on the electrodes and the energy transmitted to the electrodes will be very heterogenous, i.e. strongly decreasing from the first electrode, at the end of rapping bar subjected to impact from the hammer, to the last electrode in the row. The row may often comprise more than ten electrodes.
In the third example, in which the rapping bar acts upon an edge of each electrode, substantially a bent edge of the electrode, the peak force as well as the energy transmission is substantially uniform for all of the electrodes, but is often inadequate for attaining satisfactory rapping of the electrodes. In any event, a requisite adequately defined and desired impact is not attained since the plate thickness of the electrode and the shape of a possible bend of the electrode edge are determined by factors other than the required transmission of rapping impact to the electrodes.